I know I said this a long time ago, but now it has arrived; my PowerNow for my '03 YZ250F! It is gorgeous, light, very clean, very sano.

For those following along at home, this is the final part in my "mods before I hit the dyno" list. So now that I have it, I made my appointment for Monday! So basically I should have SOME kind of results by Tuesday, if all goes well.

Here's the plan, I can't promise anything, but this is it:

-mount Vortex ignition, but DON'T HOOK UP
-run bike as-is (stock with Boyesen water pump cover and impeller already installed)
-install PowerNow, run bike
-hook up ignition, run bike
-UNHOOK ignition! plug stock back in. install M4 pipe, run bike
-hook up ignition, run (now everything is connected)
-check air/fuel ratio, make sure jetting is right on, consider ambient temp
-keep it only slightly rich, as the temp in the shop will be around 70,
but the coldest I'll probably ride in is the 50s.
-when it's hotter the bike runs richer
-when it's colder the bike runner leaner (cold air, more dense air = more air)


I'm pretty psyched, I have a lot of work to do in a small amount of time if I want to get all these readings. I'll sure try. I'm trying to get everything organized so I can maximize my time there. The coolest part is I walk away with a pimped out 2003 YZ250F!!!! I'm really not coming into this with expectations that EVERY part is going to blow me away with its amazing power readings, but I'm just curious to see what's what. Most of all I want to see my air/fuel readings to help with my jetting of the "overall product".

I'll keep you posted!
-totally pumped

I thought you forgot! PLEASE POST THE M4 DYNO! I bought one last fall, and it is still in the box (since I live in Ohio)! I've been very interested in your results.

Nick

I thought you forgot too! Glad to see that you're moving forward with your dyno test. I will be stoked to see your results! Good LUCK!!!

-Fiddler

It will be interesting to see the results, but don't expect the PowerNow to show marked increases in the dyno chart... it is the power delivery that is affected by the Powernow or JamesNOW!, and the dyno cannot measure the power delivery characteristics or the feel, or the pulling power when you lug the bike...

The vortex will be good to see... remember to try it with different curves selected...

David

I can't wait to see the results. I'm going to do the same mods(pipe, vortex and powernow) and it's going to be interesting to see the dyno. Good work.

Put me down as one that can't what to see the results! I've been wanting to see some dyno results "real interrested in pipes". I know it's just 2 pipes "stock/vs" but I'm interrested in the Vortex too.
Good LUCK!

I have one suggestion. Do it all as you planned with one exception, don't test the PowerNow until you've done your exhaust gas readings and tweak your jetting as needed. Then add the PN and us the EGA again.

The reason I say this is the PN really seems to effect my jetting and I haven't nailed it down yet. There is definitely more throttle response and grunt down low, but the jetting seems rich. It's hard to chase because of our crazy weather right now in OK. One day it's 70 and the next it's 17.

If you add the PN first I think you will have a rich condition that you may attribute to something else. If you test it after everything else is in place you can eliminate that.

That said, I don't think the dyno will show you much improvement from the PN. It's something you can feel riding but I bet there isn't much on the dyno. If there is even one HP I would be surprized.

Good Luck!

I agree with the above posts about the PN. It shouldn't show up on the dyno since the PN works below or near 1/2 throttle and a typical dyno run is done at WOT. I had an M4 pipe on my '01 yz250f and i loved it. Steve at M4 is getting me a new one for my '03 yz250f that i bought tonight (WOO-HOO!) I haven't ridden it yet but hopefully it dosen't have the miss. let us know how the dyno results turn out and also which brand of dyno you are using. have fun!

Todd
'01 yz250F (for sale)
'03 yz250F (got it tonight!)

excellent. That's what I was looking for, some holes in my logic. OK, I will move the "adding the PowerNow" until last. I too don't expect to see any HP change, but the jetting change should be most interesting.

I'll try to remember about "what kind of dyno".

Overall I'm not so much interested in peak numbers (all dynos read different), but the improvement from one upgrade to the next. I can probably test a couple different curves on the Vortex, but man, I don't want to overstay my welcome! I'll do those at the end of the day, time (and shop dude) permitting!

The main thing I hope to accomplish is a finely jetted bike and some cool charts. I'm spending all day tomorrow in preparation for Monday. I'm taking off of work to do this at off-peak shop hours so I can hopefully get a lot of runs. But I need to get paid! So I kinda need to hurry.

-way psyched

I would suspect that if the dyno runs are WOT runs you would not see any gains with the PN, or maybe a just a little from the straigtening of the air flow. But....you may see major low RPM torque gains if you compared 1/2 throttle runs with WOT runs. You could get consistant 1/2 throttle runs if you put the throttle stop back in, but do you have a stock stop lying around?

Mike 01WR250F (I don't need no stinkin drill)

tranq,
we all can't wait till you post your results.
i agree with YZA on the PN.
what i will guess is that you will need to drop your PJ 1 size and a little tuning with the screw.

To cut a long jetting setup story short, my jetting was spot on for the area i ride and after doing the PN/JN mod at 1/3 height riding in the same weather and area my plug is sooty black at 1/4 and 1/2 throttle openings!
Going to drop the needle down one notch and fuel screw 1/4 turn back!